The present invention is directed to an endless ring-shaped crawler belt which is placed around a pair of crawler wheels and rotatably driven between such crawler wheels when one of the crawler wheels is rotatably driven.
Further, there are those in which the pair of crawler wheels is respectively structured of a sprocket wheel comprising sprocket teeth for driving one of the crawler wheels, and those in which one is a sprocket wheel and the other is a sprocketless cylindrical idler wheel for driving the sprocket wheel. Such sprocket wheels and idler wheels are hereinafter collectively referred to as crawler wheels.
This type of crawler belt is generally used on vehicles known as crawler vehicles. The ground pressure of crawler vehicles is low, and they are therefore employed for various uses; for example, construction machinery, as such crawler vehicles are capable of travelling at locations with unfavorable road conditions where ordinary vehicles with tire wheels are not able to run. As conventional crawler belts, known are steel crawler belts structured in a ring shape by linking metal shoes, and rubber crawler belts reinforced with steel wires and the like. Rubber crawler belts are often used with vehicles that sometimes travel on open roads since such belts do not damage the road surface and generate little travel noise. Nevertheless, such rubber crawler belts have problems in that the strength and durability are inferior in comparison to crawler belts structured by linking steel shoes, and in that it is necessary to replace the entire crawler belt even in cases where only a part of the crawler belt is damaged (particularly the travel face which contacts the ground). Thus, it is often necessary to utilize steel crawler belts in such cases.
Here, the steel crawler belt is superior in strength and durability and there is an advantage in that the respective shoes may be replaced or repaired separately, but there is a problem in that the travel noise from the crawler belt during the traveling motion is loud. Specifically, the faster the travelling speed, the louder the noise at an accelerated tempo. This noise is caused by the sound generated upon the connections linking the respective shoes colliding with the crawler wheel, and the sound continuously generated when the crawler belt is pulled and wound inside the drive crawler wheel and vigorously collides with the sprocket teeth of the crawler wheel structured of a sprocket wheel.
An object of the present invention is to provide a low-noise type steel crawler belt having a structure capable of reducing the travel noise while maintaining the advantages of the strength, durability and easy repairs that steel crawler belts have.
According to the present invention, an endless ring-shaped crawler belt, which is mounted on and round a pair of front and rear crawler wheels and rotatably driven between the pair of crawler wheels by rotatably driving at least one of the crawler wheels, comprises: a multiplicity of inner shoe members made of steel; a multiplicity of outer shoe members made of steel and arranged to oppose the inner shoe members, respectively; an endless ring-shaped rubber belt member retained between the inner shoe members and outer shoe members respectively opposing each other; and an endless ring-shaped steel wire member embedded in the belt member so as to extend in the longitudinal direction. The inner shoe members are arranged side by side along the inner periphery of the belt member, the outer shoe members are arranged side by side along the outer periphery of the belt member, and a multiplicity of concave portions, which are formed side by side in the longitudinal direction between the inner shoes so as to open toward the inner periphery, receive the sprocket teeth so that the crawler belt is passed round the crawler wheels.
With a crawler belt structured as described above, the crawler wheel contacts the steel inner shoe members and engages with the crawler belt, and it is thereby possible to secure the strength of the portion contacting the crawler wheel and to improve the strength and durability of the crawler belt. Further, as the steel outer shoe members mounted on the outer periphery contact the road surface, it is also possible to improve the strength and durability of such portion. And when such steel outer shoe members become worn or damaged, it is possible to independently replace each of such outer shoe members. Repair may thereby be conduced easily and at low cost. In addition, as a rubber belt member is retained between the inner and outer shoe members and such inner and outer shoe members are mounted side by side in the longitudinal direction, the noise caused by the impact of the inner shoe members and the crawler wheel is absorbed by the rubber belt member, and the travel noise is reduced thereby. Moreover, as a wire member embedded in the belt member is formed in a ring shape so as to circumvent the crawler belt, the tensility of the wire member inhibits the crawler belt from being pulled inside upon being wound into the crawler wheel. Thus, the force of the impact of the inner shoe members and the crawler wheel is weakened, and the travel noise is reduced thereby.
It is preferable that the inner shoe members are embedded in the belt member and integrated thereto in a state where the portion contacting the crawler wheel at the inner periphery and the portion connected to the outer shoe members at the outer periphery are exposed, and the outer shoe members are connected to the inner shoe members by means of bolts at the outer exposed portion of the inner shoe members. Thereby, it is possible to connect the inner shoe members in an endless ring shape while being arranged side by side on the inner face with the belt member, and a crawler belt may be prepared by respectively connecting the outer shoe members with bolts to the portion exposed to the outer face of the inner shoe members. Thus, it is possible to easily attach and detach the respective outer shoes independently. And when such outer shoe members contacting the road surface during the traveling motion become worn or damaged, it is possible to independently and easily replace each of such outer shoe members.